1. Field of the Invention
The present invention relates to a projector, and more particularly, it relates to a projector comprising a structure for cooling a source lamp.
2. Description of the Background Art
Various projectors comprising structures for cooling source lamps are proposed in general. For example, Japanese Patent Laying-Open Nos. 2000-330202 and 8-22075 (1995) disclose such projectors.
The aforementioned Japanese Patent Laying-Open No. 2000-330202 discloses a projective display (projector) discharging air, externally fed by a cooling suction fan (air feed means) through vent holes formed on the bottom surface of a housing to pass through optical units, to an exhaust fan arranged at the back of a source lamp. In this projector disclosed in Japanese Patent Laying-Open No. 2000-330202, the air flows through a path passing through the optical units to directly reach the exhaust fan, another path passing through the source lamp as well as an exhaust port formed at the back of the source lamp via vent holes formed in front of a lamp housing storing the source lamp from the optical units to reach the exhaust fan and still another path passing through a power supply unit via an auxiliary suction fan mounted on an end of the power supply unit from the optical units to reach the exhaust fan.
The aforementioned Japanese Patent Laying-Open No. 8-22075 discloses a projector, comprising a light source (source lamp) formed by a convex mirror and a light-emitting portion, feeding air introduced from a suction fan (air feed means) into a lamp house (lamp case) storing the light source through vent holes formed on the lamp house for forming reflux toward the center of the concavity of the concave mirror, thereby cooling the light emitting portion arranged at the center of the concavity.
A projector comprising a structure for cooling a source lamp and optical components is also known in general. The structure of an exemplary conventional projector of this type is described with reference to FIGS. 7 to 9.
As shown in FIG. 7, the exemplary conventional projector comprises a front frame 101, a rear frame 102, an upper frame 103 and a lower frame 104. A lens receiving portion 101a receiving a projection lens 105 for projecting images is formed on a part closer to an end (along arrow A) of the front frame 101. Exhaust slots 101b are provided on a part located between the center and the other end (along arrow B) of the front frame 101, as shown in FIGS. 7 and 8.
Intake ports 104a for introducing air are provided on a first side surface (along arrow A) of the lower frame 104 while exhaust slots 104b for discharging air are provided on a second side surface (along arrow B) thereof, as shown in FIG. 8. An exhaust fan 106 is arranged inside the exhaust slots 104b, for discharging air from the projector. A main switch 107 is provided on the first side surface (along arrow A) of the lower frame 104.
A lamp case 108 is set in the lower frame 104. A plurality of openings 108b are provided on side surfaces 108a of the lamp case 108, as shown in FIG. 9. Protection nets 109 are mounted on a group of the openings 108b provided along arrow A. These protection nets 109 have a function of preventing fragments of a source lamp 110 arranged in the lamp case 108 from scattering outward when the source lamp 110 is broken due to excessive temperature rise. The source lamp 110 arranged in the lamp case 108 comprises a bulb 110a serving as a light source and a reflector 110b for reflecting and condensing light emitted from the bulb 110a, as shown in FIG. 8.
The lower frame 104 is provided with a temperature control fan 111 for controlling the temperature of the source lamp 110 by guiding air to the source lamp 110.
An engine chassis 112 is set in the lower frame 104. A color wheel 113 is rotatably arranged on a position of the engine chassis 112 condensing the light emitted from the bulb 110a of the source lamp 110. This color wheel 113 has a function of coloring the light emitted from the source lamp 110. A light tunnel 114 for rectangularly shaping the light is mounted on the color wheel 113 along arrow A. This light tunnel 114 has an inlet 114a receiving the light from the source lamp 110 and an outlet 114b discharging the received light.
A transmission member 115 transmitting the light shaped by the light tunnel 114 is mounted on the engine chassis 112 in the vicinity of the outlet 114b of the light tunnel 114. A cooling fan 116 is set on the side of the light tunnel 114 and the transmission member 115, adjacently to the temperature control fan 111.
A mirror 117 for reflecting the light transmitted through the transmission member 115 is set in the engine chassis 112. A DMD (digital micromirror device) 118 for further reflecting the light reflected by the mirror 117 and supplying the same to the projection lens 105 is provided on the outer side of the engine chassis 112. A lens 119 is provided between the DMD 118 and the mirror 117. This lens 119 has a function of condensing the light reflected by the mirror 117 to reflecting portions of the DMD 118. The DMD 118 is mounted on a printed board 120 for controlling the same. A heat sink member 121 for releasing heat from the DMD 118 is mounted on the printed board 120. A main substrate 122 for controlling the projector is arranged on the lower frame 104.
Operations of the exemplary conventional projector are now described with reference to FIG. 8. First, the light emitted from the bulb 110a of the source lamp 110 is condensed by the reflector 110b of the source lamp 110, colored by the color wheel 113 and introduced into the inlet 114a of the light tunnel 114, as shown in FIG. 8. Thereafter the light introduced into the inlet 114a of the light tunnel 114 is rectangularly shaped, to outgo from the outlet 114b of the light tunnel 114. The light outgoing from the outlet 114b of the light tunnel 114 advances along arrow C and passes through the transmission member 115, to enter the mirror 117. The mirror 117 reflects this light along arrow D. The light reflected by the mirror 117 enters the DMD 118 through the lens 119. The DMD 118 reflects this light along arrow E, for supplying the same to the projection lens 105. Thus, the projection lens 105 projects images on a screen or the like.
In the aforementioned operations of the projector, the exhaust fan 106, the temperature control fan 111 and the cooling fan 116 are so rotated as to introduce air through the intake ports 104a of the lower frame 104. First, the cooling fan 116 is so rotated as to guide part of the air introduced through the intake ports 104a toward the color wheel 113 and the light tunnel 114 along arrow F in FIG. 8. The partial air guided toward the color wheel 113 and the light tunnel 114 passes through the color wheel 113 and the light tunnel 114, and is thereafter discharged through the exhaust slots 101b of the front frame 101. Thus, the color wheel 113 and the light tunnel 114 are cooled.
The temperature control fan 111 is so rotated as to feed another part of the air introduced through the intake ports 104a into the lamp case 108 through the openings 108b (see FIG. 9) along arrow G in FIG. 8. Thus, the partial air fed into the lamp case 108 passes through the source lamp 110 arranged in the lamp case 108, and is thereafter discharged from the exhaust slots 101b of the front frame 101 through the openings 108b of the lamp case 108. Consequently, the source lamp 110 is controlled to a prescribed temperature.
The exhaust fan 106 is so rotated as to discharge still another part of the air introduced through the intake ports 104a from the exhaust slots 104b of the lower frame 104 through the main substrate 122 along arrows H and I in FIG. 8. Thus, the main substrate 122 is cooled.
However, the conventional projector shown in FIGS. 7 to 9 must disadvantageously be provided with the temperature control fan 111 and the cooling fan 116, in order to cool the source lamp 110 as well as the color wheel 113 and the light tunnel 114. Consequently, the number of the fans (air feed means) for cooling the source lamp 110 and the optical components such as the color wheel 113 and the light tunnel 114 is disadvantageously increased.
In the aforementioned projective display disclosed in Japanese Patent Laying-Open No. 2000-330202, on the other hand, air not increased in temperature is disadvantageously discharged from the display due to the path guiding the air fed from the cooling suction fan directly to the exhaust fan through the optical units. Therefore, it is disadvantageously difficult to efficiently cool the source lamp with the air introduced through the cooling suction fan.
In the aforementioned projector disclosed in Japanese Patent Laying-Open No. 8-22075, air fed through the suction fan is introduced into the lamp house through the vent holes of the lamp house storing the light source. Therefore, this projector requires an additional fan (air feed means) independent of the suction fan in order to cool optical components arranged on a position irradiated with the light from the light source, although this is not described in the aforementioned gazette. Consequently, the number of fans (air feed means) for cooling the light source and the optical components is disadvantageously increased.